Method of severing and reuniting glass objects



May 3, 1938. c. STRINGER METHOD OF SEVERING AND REUNITING GLASS OBJECTS Filed Dec. 5, 1955 glass envelope.

Patented May 3, 1938 UNITED STATES PATENT OFFICE METHOD OF SEVERING AND REUNITING GLASS OBJECTS Louis C. Stringer, Portland, reg., assignor to Light Service Corporation, Portland, Oreg.

Application December 3, 1935, SerialNo. 52,681

1 Claim.

This invention relates generally to' glass working and particularly to the method of and apparatus for severing and reuniting glass objects.

The main object of this invention is the provision of an exceedingly simple method of opening and closing a glass object and the development of suitable apparatus for use in conjunction therewith.

The second object is to make it possible to sever and reunite glass objects or to open and close glass objects such as light bulbs, radio, television, and X-ray tubes in a manner that the elements therein may be repaired, reconditioned, or rejuvenated at but a fraction of the cost of a comvaging of the more expensive portions of electrically operated appliances contained in glass enof heating elements and their relation to the envelope.

Similar numbers of reference refer to similar parts throughout the several views.

Before entering into a description of this invention, it must be understood that it is capable of use through a very large portion of the glass working art, but is particularly well adapted to the cutting and reuniting of glass rods, tubes, lamp bulbs, or envelopes such as are used for radio, X-ray, and other appliances of a similar nature, and the explanation given .herein is merely to illustrate its adaptability to the glass workers art and the manner in which it can be used to solve the major problem in the repair of electric lamps, radio tubes, etc.

Referring in detail to the drawing, there is shown a representative form of glass envelope Ill such as is used on show case lamps ,which are provided with the usual base ll. lt.is;fassumed that the lamp has failed, either due to the severing of the filament or its destruction under use, and it is desired t6 replace the filament thereof.

If the operation to be performed is one which requires the removal of the lamp base, this is accomplished under ordinary conditions by merely heating the base II. This may, of course, be done velopes by providinga completely practical methe .s after the severing Operation is perod of replacing, repairing, or reconditioning. the defective elements and then reenclosing it rains This invention is especially applicable to deviceswherein the functioning unit is contained parentfrom the specification following as illustrated in the accompanying drawing, in which:

Fig. 1 is a side elevation of a representative form of tube. I

Fig. 2 is an elevation similar to Fig. 1 but with a portion broken awaygn longitudinal section to show score marks. i

Fig. 3 is a view similar to Fig. 2 showin a resistance wire disposed around the score mark.

Fig. 4 is a section taken along the line 4-4 in Fig. 3, showing the electric arrangement for the severing device.

Fig. 5 xis a fragmentary'section showing the severed object. V

Fig. 6 is a side elevation showing a revolvable head for supporting an object while subjecting same to heat-uniformly along the line where it has been severed.

formed. In order to sever the envelope or bulb for the purpose of making the enclosed parts accessible, it is now placed in a rotating holder, not shown, where at a desired line an abrasive or scoring tool is brought into contact with the exterior of'the envelope l0 while it is revolving,

thereby producing the score mark l2 which encircles the envelope Hi. This mark is preferably continuous but may contain one or more breaks for the purpose of producing a slight wave in the line in order to expedite the restoring of the parts to their original relationship. It is some- 40 times desirable to warm the envelope l0 before it is scored. The envelope I0, after being scored, and while it is at a normal temperature, is now encircled by a resistance wire l3, which is brought into register with the score mark I2, and placed in series with a small step-down transformer I4 and the rheostat IS. The purpose of this arrangement is to make it possible to sever the tube or envelope ID in a perfectly straight plane.

The envelope i0 having been severed is now prepared for whatever operation is necessary for its restoration to usefulness. After such repair or alteration has been made, the envelope I0 is ready to be assembled. After all the details of 55 been preheated to a temperature of approximately 350 F., then electric energy is applied through proper conductors to suitable electrodes, not shown, so spacedand connected as to produce a series of arcs suflicient to encompass the entire circumference of the envelope l0 along the line previously severed. It must be understood that this is being done while the envelope is rotated on the holder l6 and that sufficient heat is being applied to liquefythe two ends or portions of the envelope l0, care being taken to prevent the arcs from rendering the walls liquid over too great an area, thereby causing the portion of the member being heated to bulge, buckle, or collapse. With the proper amount of care, the possibility of loss will be reduced to a minimum.

The fusing of the glass, as stated, and the weight of the uppermost portion causes the tube parts to reunite in cylindrical form, leaving little or no indication of a joint. It is, of course, understood that after this operation is complete, the tube or envelope l0 must be properly annealed. While I have described the fusing operation as being performed by means of an electric are, it is desirable especially with larger and heavier globes and tubes to use controlled gas flames disposed around the rotating envelope, thereby increasing the uniformity of the heat application. It must be understood that the glass articles should be properly shielded against drafts of air and-shocks in order to obtain the best possible results. r

By a controlled gas flame is meant a flame with'a knife-like edge which can be so oriented that the maximum heat will be applied to the line of contact between the two tube ends bein united, it being a matter of common knowledge that the ability of even expert glassblowers to unite thin walled glass. tubes with the aid of cross-fire burners is limited to tubes of relatively small diameter; but by the use of the controlled gas flame, tubes may be joined successfully and smoothly even when the tube diameter is relatively great and the wall is relatively thin. Inasmuch as this invention is particularly directed to the rebuilding of light bulbs and similar con-' trivances, the necks of which are fairly large in diameter and the walls of which are very thin, the use of a controlled application of heat is of utmost importance.

While reference. has been made to electric lamps and the repair thereof, it must be understood that this invention relates particularly to the separation of and the reuniting of the walls of a glass envelope. While those having a circular cross section are most common, other shapes may be cut and reunited with equal success by merely providing a means for the uniform application of heat about the periphery thereof.

I am, of course, aware that in the past objects made of glass have been severed and reunited, and it is therefore not my intention to broadly cover such processes or apparatus for performing same; but I do intend to cover all such forms and modifications of my invention as fall fairly within the appended claim.

I claim:

A method of severing glass objects consisting of progressively scoring a mark along the line of severance, then applying heat along the score line with a rising temperature, the application of said heat being limited to substantially the width of the scoring and simultaneously along the length of the score mark.

LOUIS- C. STRINGER. 

